Amorphous alloys have been developed since 1970s as a soft magnetic material with outstanding magnetic performance. Its manufacture technique is simple and its cost is inexpensive. The outstanding performance and other good properties for this kind of soft magnetic amorphous material can be only obtained by heat-treatment.
Most of the amorphous materials have a common shortcoming which is their poor resistance to oxidization. Therefore, it is necessary to put them in a protecting atmosphere when heat-treated. For example, the large amount commercially available Fe-Ni based soft magnetic alloy 2826 (FeNiBP) and 2826 (FeNiMoB) are heat-treated necessarily in a protecting atmosphere. The Ferric based alloy described in JP 60-128248, an amorphous with low magnetostriction, also has to be heat treated in a protecting atmosphere to obtain the properties needed.
Because of the necessity of the protecting atmosphere for heat-treatment, the production cost has been increased and the productivity has been limited.
In addition, a complex magnetic head material with large magnetostriction disclosed in JP 61-194609 is sensitive to stress. Another non-magnetic material used for welding (U.S. Pat. No. 4,503,085) has poor performance when processed and ow rate of finished product in ribbon formation.
Using 2826 (FeNiBP) as a base, Cr and Si are added to the Fe-Ni based high permeability amorphous alloy and the content of P is reduced; excellent magnetic properties have been obtained after heat-treated in air.